1. Field of the Invention
The present invention relates to a semiconductor device and more particularly to a semiconductor device provided with a slew rate control signal generating circuit.
2. Description of Related Art
In recent years, some semiconductor devices are provided with a slew rate control signal generating circuit (refer to Japanese Patent Application Laid-open No. 2005-182994, for example). The slew rate control signal generating circuit controls slew rate of an output circuit in accordance with a slew rate control signal so that delay times at a rising edge coincides with a falling edge of an output waveform on a receiver side.
In the aforementioned kind of semiconductor device, power supply noise may occur in a source power that is supplied to an output buffer circuit caused by changing an output data signal. A power supply for supplying a source power to the output buffer circuit may be provided independently of a power supply for supplying a source power to other circuits in order to prevent the power supply noise from propagating. Since source power supplied to a circuit for generating the slew rate control signal differs from source power supplied to an output buffer circuit which receives the slew rate control signal in such a semiconductor device, however, there is a problem that it is difficult to precisely control slew rate of the output buffer circuit if noise occurs in the source power supplied to the output buffer circuit.